1. Field of the Invention
The embodiment discussed herein relates to a reference voltage generation circuit and a semiconductor device.
2. Background of the Related Art
In recent years, a semiconductor device, called an IPS (Intelligent Power Switch) is under development, which is obtained by integrating, into one chip, a switch element using a power semiconductor element, a driver circuit for the switch element, its peripheral control circuit, its protection circuit, and the like.
The IPS is widely utilized in automotive electric systems, for example, such as a transmission, an engine, and a brake, and thus products achieving smaller size, higher performance, and higher reliability are desired.
As the conventional technique, there is proposed a technique for preventing a malfunction of a circuit by fixing a potential using the clamp breakdown voltage of a Zener diode (US Patent Application Publication No. 2012/0287684).
In a high-side IPS having a switch element interposed between the positive electrode of a power supply and a load, a voltage lower than a power-supply voltage by a specified level is generated and the voltage lowered by the specified level is supplied as an internal ground for driving the circuit inside the IPS.
Moreover, in the IPS, when the switch element is turned on, an electric charge is accumulated by a charge pump until a threshold voltage of the switch element is exceeded, and then the accumulated electric charge is applied to the gate of the switch element to turn on the switch element.
However, the charge pump performs an operation of accumulating an electric charge by repeating the charging and discharging of a capacitor at high speed using an oscillation circuit, and therefore due to this influence, conventionally the potential of the internal ground might significantly fluctuate. If the potential of the internal ground fluctuates, a circuit will malfunction to cause a reduction in quality.